1. Field of the Invention
The present invention relates to a solid cosmetic composition. More particularly, the present invention relates to a solid cosmetic composition with superior shape-retaining ability, superior spreadability, and gloss.
2. Description of the Related Art
In the cosmetic field, lipstick, lip-balm, foundation, pencil shaped cosmetics, and hair stick are known as solid cosmetic compositions.
Among these, oil-based solid cosmetic compositions is (a) a liquid oil component such as caster oil, jojoba oil, squalene, lanolin, chemically synthesized ester oil, liquid paraffin, and (b) a wax component which is a solidifier such as carnauba wax, candelilla wax, ceresin wax, microcrystalline wax, hydrogenated animal oil, hydrogenated vegetable oil, beeswax, and (c) a powder component. The powder component is dispersed in the mixture of liquid oil component and wax component.
Generally, the product must satisfy the shape-retaining ability and usability. Usability requires especially good spreadability and gloss, which is controlled by the blending ratio of a wax component and a liquid oil component. But it is quite difficult to satisfy the demands for enough shape-retaining ability and good usability simultaneously. Because the wax component is an essential ingredient for solidifying the liquid oil component, it should be a large amount of the formula in order to retain the product shape while in use and in order to allow storing at various temperatures. When the amount of the wax component is high, spreadability of the product tends to be heavy, and the gloss that is provided by the liquid oil component tends to be decreased. Because of this contradiction, it is difficult to satisfy the demands for enough shape-retaining ability and good usability simultaneously. It is also demanded that a solid cosmetic composition have superior shape-retaining ability and usability for a long period of time.
In order to solve the above-mentioned problem, a small amount of wax giving high hardness to the product may be selected Such a wax usually has a high melting point and there is a problem that it is not easy to produce. Such a wax requires additional heating process in order to melt the wax ingredient at a high temperature during production and the filling property tends to become undesirable due to the relatively high melting point. Further more, when the solid cosmetic composition contains water such as an emulsified type lipstick, extra heating at high temperature causes loss of the water ingredient.
An object of the present invention is to provide a solid cosmetic composition, which dramatically improves the shape retaining ability and usability without an extra heating process, which avoids a problem of the high melting point of the wax ingredient.
The inventors conducted research to solve the aforementioned problem and discovered that when combining a) Fischer-Tropsch wax having average molecular weight of 300 to 1200 and b) Microcrystalline wax in a specific ratio, that the liquid oil component when solidified was unexpectedly high hardness. It was without loss of good spreadability and gloss and extra heating process during the production.
The present invention relates to a wax composition, which gives enough hardness to a product such as solid cosmetics, which contain a liquid oil component. The invention provides solid cosmetics having superior shape-retaining ability and spreadability and gloss. The aforementioned problem due to the high melting point of wax ingredient is eliminated.
The present invention relates to a solid cosmetic composition comprising:
(a) Fischer-Tropsch wax having an average molecular weight of 300 to 1200 and
(b) Microcrystalline wax and (a):(b)=60:40 to 99.9:0.1 by weight ratio.
The present invention relates to a solid cosmetic composition further comprising a liquid oil component.
The present invention relates to a solid cosmetic composition comprising a solidifier consisting of wax components (a) and (b).
The present invention relates to a solid cosmetic composition further comprising a colorant and/or pigment.
The present invention relates to a solid cosmetic composition such as lip stick.
The present invention relates to a wax composition comprising:
(a) Fischer-Tropsch wax having average molecular weight of 300 to 1200.
(b) Microcrystalline wax and (a):(b)=60:40 to 99.9:0.1 by weight ratio.
The present invention is described in detail below.
In the present invention, the ingredient (a) Fischer-Tropsch wax is a synthetic hydrocarbon wax, obtained by the xe2x80x9cFischer-Tropsch synthesisxe2x80x9d, which has an average molecular weight of 300 to 1200, and preferably 400 to 1100, and more preferably 500 to 700.
When the average molecular weight of Fischer-Tropsch wax is less than 300, solidability tends to be decreased. When the average molecular weight of Fischer-Tropsch was is more than 1200, the melting point of the wax is too high to produce the produce the product and extra processes are required. The average molecular weight in this specification is calculated by a conventional method, and it is defined as xe2x80x9cMean average molecular weight,xe2x80x9d which is the number-average molecular weight.
In the present invention, an average molecular weight in the above mentioned range is necessary. It is preferable to use a Fischer-Tropsch wax having a molecular distribution curve with a sharp peak, in order to close to single distribution of the molecular range.
Fischer-Tropsch wax in the present invention is available as commercial product. For example, commercial products having an average molecular weight of 300 to 1200 are as follows: xe2x80x9cParaflint C77xe2x80x9d, xe2x80x9cParaflintC80xe2x80x9d, xe2x80x9cParaflint H1xe2x80x9d (Products of SCHUMANN SAZOL.LTD.) xe2x80x9cFT100xe2x80x9d, xe2x80x9cMDP-7010xe2x80x9d (Products of NIPPON SEIRO CO., LTD.)
The amount of the ingredient (a) is defined according to the aforementioned specific range of the ratio of ingredient (a) and (b), it is preferably 0.06 to 29.97 mass %, more preferably 0.6 to 19.98 mass %, and more preferably 3.0 to 14.98 mass % in the total solid cosmetic composition.
For Ingredient (b) of the present invention, microcrystalline wax is a hydrocarbon wax conventionally used in cosmetic compositions such as lipstick, creams and the like. It uses a commercially available material. It is preferable that the Microcrystalline wax have a melting point which is 70xc2x0 C. or more, and less than 100xc2x0 C. and more preferably more than 80 to 95xc2x0 C. for best shape-retaining ability. The amount of the ingredient (b) Microcrystalline wax formulated in the present invention is 0.01 to 12 mass %, preferably 0.05 to 8 mass %, more preferably 0.25 to 6 mass % in the total solid cosmetic composition.
In the present invention, when the wax composition, the blended ingredients (a) and (b) are in the ratio of (a):(b)=60:40 to 99.0:0.1 (in mass ratio), the composition can be used as solidifier in a solid cosmetic composition.
The blend ratio of (a) and (b) is preferably (a):(b)=80:20 to 99.8:0.2 (in mass ratio), and more preferably (a):(b)=90:10 to 95:5 (in mass ratio).
When ingredients (a) and (b) are blended in aforementioned ratio, the hardness of the product has a critical point and the wax component has an excellent effect as solidifier.
In the present invention, the wax component is blended just by mixing ingredient (a) and (b), in the aforementioned ratios, and the pre-mixed wax component can be used for raw material for solid cosmetics. Furthermore, ingredients (a) and (b) can be separately mixed to a liquid oil component and blended into the solid cosmetic composition in the process of the production.
Since this wax composition gives only enough hardness to the solid cosmetic composition, spreadability and gloss are not deteriorated. The solid cosmetic composition containing this wax composition has an excellent shape-retaining ability without a problem of a high melting point in the production process.
The wax composition of the present invention has a good solidifier property for the liquid oil component. It has great value as a substitute material for the conventionally used solidifier such as ceresin wax.
The amount of the wax composition (total amount of ingredient (a) and (b)) to total amount of the solid cosmetic composition, it is defined according to the type of solid cosmetic composition. It is preferably 0.1 to 30 mass % of total amount of a solid cosmetic, more preferably 1 to 20 mass %, more particularly preferably 5 to 15 mass % to total amount of a solid cosmetic. If the blend ratio is less than 0.1 mass %, the solidifier effect is not performed and the shape-retaining ability of the product tends to be a problem On the other hand, if the blend ratio is more than 30 mass %, the hardness of the product of the solid cosmetic tends to be too hard and good spreadability and gloss tend to deteriorate.
In the present invention, the liquid oil component is in a liquid form at ordinary temperatures (15xc2x0 C.). The oil is not limited and available for this invention if the oil is usable for cosmetics.
Preferably examples of the liquid oil component are as follows:
Glyceryl tri-2-ethylhexsanoate, glyceryl diisostearate, diisostearyl malate, dimethyl polysiloxane, decamethyl pentasiloxane, macademia nuts oil, trimethylolpropane trioctanoate, diglyceryl triisostearate, heptylundecyl hydroxystearate, jojoba oil, squarane, liquid lanolin, glyceryl triisostearate/hydrogenated rosinate, methylphenyl polysiloxane, glyceryl triusostearate, and polybutene.
It is particulaly preferable for lipstick compositions and other compositions for lips, to use liquid lanolin, glyceryl triisostearate/hydrogenated rosinate, methylphenyl polysiloxane, glyceryl triisostearate, or polybutene.
It is preferable in terms of long lastingness (lasting power: staying on the skin for long time against a sebum) when it is applied to the skin, to use volatile liquid oils (ring type silicone oils such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane).
The amount of liquid oil component formulated in the present invention is preferably 30 to 99.9 mass %, and more preferably 50 to 59 mass % in the total solid cosmetic composition.
When the amount of liquid oil component is little, spreadability tends to be heavy.
In the present invention of a solid cosmetic composition, in addition to a liquid oil, if necessary, it can also be blended into a solid oil component and/or into semi-solid oil component.
In addition to the aforementioned essential ingredients, any other ingredients, which are commonly blended in solid cosmetic compositions, can be blended in if they do not deteriorate the effect of the present invention. For example: other waxes, other oils, humectants, preservatives, antioxidants, ultraviolet absorbers, ultraviolet scattering agents, polymers, surface active agents, colorants, pigments, powders, drugs, alcohols, solvents, fragrances, flavors, etc, are available. The solid cosmetic composition of the present invention can be produced by common production process.
In the present invention, specific examples of solid cosmetic compositions are as follows: Make-up cosmetics such as lipstick, lip-gloss, lip balm, foundations, eye shadow, hair cosmetics such as hair stick, and pomades are examples. The solid cosmetic compositions refer to a broad range of compositions used for cosmetics and are not limited to a solid cosmetic composition. A stick form solid cosmetic is preferable, especially a lipstick containing a pigment and/or a colorant.
In the present invention, the solid cosmetic composition is in solid form at ordinary room temperature (25xc2x0 C.).
The solid cosmetic composition of the present invention having superior shape-retaining ability and usability is obtained by blending a wax component of aforementioned ingredient (a) having particular average molecular weight, and the ingredient (b). Reason of the effect is not known, but it is believed to be as follows.
The solid cosmetic composition comprising the wax component and the liquid oil component has a network structure of a wax component in micro crystal form, when the wax and oil are combined with each other, the liquid oil component is included in this structure and the shape stays in solid form.
The shape and size of the wax micro-crystal structure, and the types of the liquid oil components form the structure and character of the solid cosmetics. The wax composition of the present invention is balanced to maximize the shape-retaining ability and usability by solidifying the liquid oil component.